[Bug c/101964] New: using scanf makes compiler never terminate

[Bug c/101964] New: using scanf makes compiler never terminate

[mateusmoraisdias3 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

            Bug ID: 101964
           Summary: using scanf makes compiler never terminate
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mateusmoraisdias3 at gmail dot com
  Target Milestone: ---

OS: 5.13.8-1-MANJARO - x86_64

Description:
using a simple call with `scanf` makes gcc never compile the source. Even a
file (the bin output) is created, but once ran nothing happens, as it were
stuck in a empty loop.

Steps to reproduce:
write a file with this content
```c
#!/main.c
#include  <stdio.h>

int main(){
    int x;
    scanf("%d", x);
    return 0;
}
```
type `gcc main.c -o main` to compile.

[Bug c/101964] using scanf makes compiler never terminate

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---

<source>:6:13: warning: format '%d' expects argument of type 'int*', but
argument 2 has type 'int' [-Wformat=]
    6 |     scanf("%d", x);
      |            ~^   ~
      |             |   |
      |             |   int
      |             int*
<source>:6:10: warning: 'x' is used uninitialized [-Wuninitialized]
    6 |     scanf("%d", x);
      |     ~~~~~^~~~~~~~~

[Bug c/101964] using scanf makes compiler never terminate

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|INVALID                     |---
             Status|RESOLVED                    |UNCONFIRMED

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Works for me.

[Bug c/101964] using scanf makes compiler never terminate

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org
         Resolution|---                         |INVALID
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
Same for me.

[Bug c/101964] using scanf makes compiler never terminate

[mateusmoraisdias3 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

--- Comment #4 from Mateus Morais Dias de Souza <mateusmoraisdias3 at gmail dot com> ---
I figured it out. My build script was something like this:
```bash
set -e
gcc main.c -o main
./main
```
for some reason gcc was not warning about my unseen error, then it ran the
program (because I forgot that it was encoded to run after building) and I
didn't notice. Running directly the gcc line into the terminal didn't show me
the warning too. But anyway, problem solved.
Sorry for openning a false-positive issue. Closing it now.

[Bug c/101964] using scanf makes compiler never terminate

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Mateus Morais Dias de Souza from comment #4)
> I figured it out. My build script was something like this:
> ```bash
> set -e
> gcc main.c -o main
> ./main
> ```
> for some reason gcc was not warning about my unseen error,

Because you didn't tell it to.

Use -Wall to enable warnings. I asked you to read https://gcc.gnu.org/bugs/
before reporting the bug, and one of the things that tells you to do is enable
warnings.

[Bug c/101964] using scanf makes compiler never terminate

[mateusmoraisdias3 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101964

--- Comment #6 from Mateus Morais Dias de Souza <mateusmoraisdias3 at gmail dot com> ---
I was a wrong of me, my apologizes. I'll not do it again